Internal combustion engine manufacturers are constantly investigating ways to improve the fuel efficiency of their products, as well as the methods for manufacturing the same. One method to improve fuel efficiency is to reduce friction losses associated with the camshaft. To implement low friction camshaft technology with a tunnel bearing camshaft design, outer races need to be installed in the cylinder block or cylinder head from either only a front side or only a rear side of the engine. This method of installation may be somewhat difficult in many applications due limited access to the journal locations within the engine. Some low friction camshaft assemblies may include camshafts having journals of various outer diameters, which may increase the rolling speed of the roller bearings on the journal having the largest outer diameter thus adversely affecting the durability and performance of the camshaft.
Accordingly, there is a need for a camshaft and method for installing the same in an engine, which enables low friction technology to improve the fuel efficiency of the engine, maintain performance of the camshaft and provide ease of manufacture.